According to a bulging device and a bulging method using a profile element pipe, for example, even when a profile steel pipe having a cross sectional shape varying in the axial direction as in a tapered pipe is hydraulically bulged, a bulging in which an internal pressure loading and an axial pressing are combined with each other can be performed to provide a larger expansion ratio than a conventional case and a joining and socket connection thereof to the other part can also be easily performed.